The thesis explores the properties of random surfaces, focusing on their significance in contact. It bridges the gap between surface contact behavior and surface specification methods. The work uses theories from random processes to analyze surface profiles as random signals, examining their impact on surface properties. Experimental data from well-instrumented experiments support a stochastic approach to tribology. The study also addresses the generation of random surfaces, aiming to classify them based on functional behavior and generation details. Techniques include stylus instruments, digital data analysis, and optical and scanning electron microscopy for surface measurement. The thesis discusses surface topography, contact mechanics, and the influence of surface finish on wear and friction. It also presents a model of surface profiles as random signals with Gaussian height distribution and exponential autocorrelation. The work concludes with a classification of surfaces based on their characteristics and the need for further research to integrate contact theory with modern surface measurement techniques. The thesis is supported by experiments and data analysis, with contributions from various institutions and individuals.The thesis explores the properties of random surfaces, focusing on their significance in contact. It bridges the gap between surface contact behavior and surface specification methods. The work uses theories from random processes to analyze surface profiles as random signals, examining their impact on surface properties. Experimental data from well-instrumented experiments support a stochastic approach to tribology. The study also addresses the generation of random surfaces, aiming to classify them based on functional behavior and generation details. Techniques include stylus instruments, digital data analysis, and optical and scanning electron microscopy for surface measurement. The thesis discusses surface topography, contact mechanics, and the influence of surface finish on wear and friction. It also presents a model of surface profiles as random signals with Gaussian height distribution and exponential autocorrelation. The work concludes with a classification of surfaces based on their characteristics and the need for further research to integrate contact theory with modern surface measurement techniques. The thesis is supported by experiments and data analysis, with contributions from various institutions and individuals.